Table 2.

Recovery of each hydroxybutyrate from human saliva

Hydroxybutyrate	Amount added (pmol)	Average recoverya [mean ± SD (n)] (%)
3HB	51.2	103.4 ± 3.6 (6)
	103.2	104.6 ± 1.6 (6)
	154.4	102.1 ± 1.1 (6)
3HIB	50.0	98.5 ± 2.0 (6)
	100.0	99.7 ± 1.0 (6)
	150.0	100.7 ± 1.1 (6)
3HMB	3.8	104.8 ± 1.5 (6)
	7.6	107.7 ± 0.6 (6)
	11.4	107.9 ± 0.9 (6)
2HB	19.2	108.8 ± 5.4 (6)
	38.4	118.8 ± 2.2 (6)
	57.6	108.7 ± 2.5 (6)

Known amounts of each hydroxybutyrate were spiked into 5 µL of human saliva collected from healthy subjects before sample preparation

^aRecovery (%) = (amount found − ${\overline{X}}_0$)/amount added × 100; ${\overline{X}}_0$ value was obtained from Table 1